[Simh] PDP-10 Home Block and KS10 Boot Code

Rob Doyle radioengr at gmail.com
Fri May 29 03:02:05 EDT 2015


I was looking at the KS10 boot code in SIMH.

The boot code looks for the Primary Home Block in disk block 1 and 
Secondary Home Block in disk block 8.

/* movei 2,10    ; blk #10 */
/* jsp 17,rdbl   ; read    */
/* movs 3,1000   ; id word */
/* caie 3,sixbit /HOM/     */

It looks to me like the Secondary Home Block is 10 (decimal)
not 10 (octal). I see it at offset 10240 (decimal) in the disk image.

Is the SIMH boot code correct?

I'm guessing that it never fails over to the secondary home block so
nobody ever noticed.

Rob.


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